Flexible joint for waveguides



`Maly 6, 1947. R. G. OLDEN FLEXIBLE JOINT FOR WAVEGUIDES Filed Sept. 30, 1944 Patented May 6, 1947 UNITED STATES. PATENT.. OFFICE..

FLEXIBLE JOINT FOR WAVEGUIDES RogerV (fr.` Olden, Princeton .'Iownship, '.Mercerf County,vN.A J., assigner to Radio Corporation of: America, a corporation of Delaware Application September 30, 1944, Serial No. 556,520'

7 Claims.

Thisyinventionwrelates generally tov electric wave transmission systems and' more particularly to an improved exible joint for use in Waveguides.'-

Heretofore, various types .of flexible waveguidev structures and joints have been employed.` One type of'exible waveguide in common use comprises a spirally-wound conductor in which successive convolutions overlap in a manner similar to that employed in conventional BX power cable shields. The principal disadvantage of exible waveguide-,construction of the spiral type is that relatively poor electrical contactis made between successive conductor; convolutions. Itis wellknown in the art that; due to relatively ,high f circulatingcurrents on `the inner surface of a waveguide, poor" contact between adjacent portions thereof provides undesired resistive losses.v

Anotherl type of flexible joint employed: be-

tween -adjacent rigid portions of conventional s waveguide transmission systems comprisescurved telescoping rigid or iiexible conductiveselementsA which also have the same disadvantage .with respect to losses due to erratic electrical contact Flexible rubber coupllngsbetween adjacent rigid waveguide sections between adjacent parts.

introduce serious wave discontinuitiesA and, in addition, usually involve objectionable wave ab sorption from the waveguide system.

'I'he instant invention comprises a novel iiexible joint for a waveguide transmission system` which-permits adjustment of the waveguide direction over an angle of the order of 60Y with a minimum of sliding contacts between, adjacent conductive elements. Since all contactsare: of

the v:wiping variety, and since special preparation ofthe wiping surfaces is not required, erratic contact eiects are reduced to a minimum with an extremely economical and practical construction.

Briefly, the `invention comprises a frame whichy supports two cylindraceous'. journal members having liat .inner-.surfaces which form an open.-I

ing for the waveguide path and which provide 1 limitingvmeans, for controlling the movement of theA adjustable portions of the-joint. A pair of'. complementary bearing members are journaled:

on-,ftheouter surfaces of the journal members andA arranged to rotate vthereabout, throughout the desired adjustment angle. A pair ofV flatexible. conductive elements, supported,` at ad'- jacentendsjofthe bearing members, extend into thelopening formed between the inner-surfaces End plates, iixedrto the frame, close the' adjacent endsof theat flexible.,

of the journalv members.

members-toY formrthe'rebetween a vrectangularwave path, the direction of which may be ad-v justed by rotation ofthe rotatable bearing mem- Y to engage a terminating ange of a conventional wave guide, ywhile`the adjustable bearing mem` ber may include a Vwavehorn or other wave terminating means.

Among thev objects of the invention are to provide anv improved iiexible joint for a Wave-f guidetransmission system. Another object of thexinvention is tor provide an improved iiexible waveguide joint including means for coupling saidl joint to a conventional waveguide transmission system; An additional object of ltheinvention is rto provide an improvedf waveguide iiexible joint which is angularly adjustable to a prede-l' termined degree. A further object of the invention is to provide an improved waveguide joint which is angularly adjustable to a predetermined degree, wherein all sliding mechanical parts may be readily llubricatedV and -wherein contacting electrical elements 'are of the wiping variety. Another object of the'invention is to provide an improvedflexible joint for coupling a rectangular waveguideto a conventional microwave horn.

Thei invention will be described in further detail by reference to the accompanying drawing of'whichA Figure A1 is a rightk elevational view of a preferred embodiment of the invention, Figure 2 is a cross-sectional vview of the device taken along the section line II-II of Figure 1 and Figure 3 is a cross-sectional view similar to the. viewof Figure .2 vbut showing :the angular adjustment-'of the device;V imilarfreference char- :acters are applied to lsimilar elements .throughout the drawing.

Referring to the draWlng,-an embodiment of the invention Vis disclosed `Which is particularly advantageous foruse withV a wave image `trans-` missionsystem ofthe general type describedin.L the. copending application' or" Harley. A. .Ia-ms-4 et al., Serial No. 531,628', iilecl April 18, 19,44. In the device described-insaid ccpendin'g application, a relativelywide, thin beam of microwave 'energy is 'radiated forscanningqa scene Ain amI cured to the supporting frame members I, 3 bymeans of screws 23, 25, respectively. The journal members I9, 2| are shaped to provide a circular external journal surface. 21V with coacting substantially fiat inner surfaces 29, adjacent'ends of which coincide with the aperture I1 between the frame supporting members I, 3.

A pair of complementary bearing members 3|,

33, supported by a frame 34, engage the journal surface 21 in a manner wherely the bearing may berotated about the journal. A pair of substantially fiat, flexible, conductive elements 35, 31;V

comprising for example, beryllium copper or phosphor bronze, are secured to adjacent ends of thev rotatable bearing elements 3|, 33. The

ends of the conductive elements 35, 31 wipeV against, or closely mesh with, the inner-surfaces of auxiliary high-conductive end plates 39, 41, and the ends'of the flexible elements remote from the bearing members 3|, 33 wipe against-the fiat inner surfaces of the journal members I9, 2|. Thus the aperture formed between the supporting frame members I, 3 coincides with the aperture formedbetween theY flexible conductive elements 35, 31 and the/auxiliary en'd plates 39, 4I to provide an adjustable wave path which passes through a suitable aperture 43 in the bearing support plate 34 to provide wave accessto a wave matching device such, for example, as a wave horn 45; A conventional waveguide 41 connected toa source of microwave energy, not shown, may be connected to the waveguide joint in any manner known in the art.

Figure 3'il1ustrates the slight deformation of the iiexible conductive elements 3-5, 31 when the bearing elements 3|, 33 are rotated through an angle of the order of 30 from the axis of the waveguide 41. By means of suitable mechanical coupling, not shown, the iiexible waveguide joint thus provided may be motor-driven to provide continuous angular adjustment at anyk desired rate and throughout a substantial angle.

Suitable lubrication may be provided for the journal surface 21 without affecting the electrical contact between the iiexible elements 35, 31 and the corresponding inner surfaces 29 of the journal members. Due to the positive wiping contact of the journal inner surfaces 29 by meansV of the flexible elements 35, 31, erratic electrical contact therebetween is minimized.

Thus the invention described and claimed hereinafter comprises an improved waveguide flexible joint mechanism providingA economical and vefficient means for adjusting the direction of Vwaves'propagated through a. waveguide transmission system.

I claim as my invention:

1. A flexible joint for a waveguide transmission Asystem comprising a fixed split journa1' having inner surfaces forming a wedge-shaped aperture opening into said waveguide, said inner surfacesproviding means for limiting the movement of said joint, a complementary apertured bearing journaled on the outer surfaces of said xed journal, andiiexible conductiveelements secured to said bearing adjacent the aperture therein and arranged to contact and slide upon said inner surfaces of said xed journal, whereby said iiexible elements comprise opposite walls of a wave transmission path through said joint and said bearing aperture.

2. A flexible joint for a. waveguide transmission system comprising a pair of fixed-split journa1 members having inner surfaces forming a central wedge-shaped aperture opening into said waveguide, said inner surfaces providing means for limiting the movement of said joint, a pair of complementary split bearing members journaled on the outer surfaces of said fixed journa1 members and providing a wave aperture from said central aperture, and a pair of iiexible conductive elements secured to said bearing members adjacent said bearing aperture and arranged to contact and slide upon said inner surfaces of said fixed members, whereby said flexible elements compriseopposite walls of a wave transmission path through said joint and said bearing ape!"- ture.

3. A flexible joint for a rectangular waveguide transmissionsystem comprising a pair of fixed split Vjournal members having substantiallyfiat inner surfaces forming opposite sides vof a central wedge-shaped'aperture Vopening into Asaid waveguide, said inner surfaces providing meansV for limiting the movement of said joint, a pairV of complementary split bearing members journaled on the outer surfaces of said fixed 'journalfmemi` bers and providing a wave aperture from '.said

central aperture, and a pair'of iiexible substantially flat conductive elements'secured to adja` y cent portions'of saidbearing members on opposite sides of said wave apertureand arranged'to contact and slide upon said'inner surfaces of said xed members, whereby said ii'exible'y elements comprise opposite walls `of a'rectangularcrossf 4 section waveY transmission path through said joint and said'bearing wave aperture. l

4. A exible joint'for awaveguide transmission system comprising a supporting-i frame having a central opening, a pair of fixed split journal members having'substantially flat innersurfaces forming opposite sides of a central wedge shaped aperture opening into said waveguide through said frame opening, said inner surfaces providing means for limiting the movement of said joint, means for supporting said journal members on said frame, a pair of complementary split bearing members journaled on the outer surfaces of said fixed journa1 members and provid-ing a wave aperture from said central aperture, and a pair of flexible substantially iiat conductive elements secured to adjacent portions of said bearing members on opposite sides of said wave aperture and arranged to contact and slide upon said inner surfaces of said fixed members, whereby said iiexible elements comprise opposite walls of a rectangular cross-section wave transmission path through said joint and said bearing wave aperture.

5. Apparatus as described in claim 4 including means for connecting a waveguide to said" supporting frame at said central opening therein in a manner whereby waves may be propagated through said aperturesA forming the wave transmission path of said joint.

6. Apparatus as described in claim 4 includin a. tapered wave horn supported by said bearing members adjacent said bearing aperture. for.

matching said wave transmissionpath toan' adjacent wave'transmission medium'.

10 bearing wave aperture.

6 a pair of flexible substantially atconductive elements secured to adjacent portions of said bearing members on opposite sides of said wave aperture substantially longitudinally coextensive therewith, and arranged to contact and slide upon said inner surfaces of said xed members, whereby said flexible elements and said end plates comprise opposite respective walls of a. wave transmission path through said joint and said ROGER G. OLDEN. 

